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      <a id="system"></a>
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      <a id="Indexsystem_i" class="indexterm"></a>
      <a id="Indexsystem" class="indexterm"></a>
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        <h2>
          <span class="refentrytitle">system</span>
        </h2>
        <p>system — 
      Call an external program via the system call
    </p>
      </div>
      <div class="refsect1">
        <a id="idp154766336"></a>
        <h2>Description</h2>
        <p>
      <span class="command"><strong>system</strong></span> and <span class="command"><strong>system_i</strong></span> call
    any external command understood by the operating system, similarly
    to the C function     system(). <span class="command"><strong>system_i</strong></span> runs
    at i-time only, while 
      <span class="command"><strong>system</strong></span> runs both at initialization and
      performance time. 
    </p>
      </div>
      <div class="refsect1">
        <a id="idp154770720"></a>
        <h2>Syntax</h2>
        <pre class="synopsis">ires <span class="command"><strong>system_i</strong></span> itrig, Scmd, [inowait]</pre>
        <pre class="synopsis">kres <span class="command"><strong>system</strong></span> ktrig, Scmd, [knowait]</pre>
      </div>
      <div class="refsect1">
        <a id="idp154774368"></a>
        <h2>Initialization</h2>
        <p>
      <span class="emphasis"><em>Scmd</em></span> -- command string
    </p>
        <p>
      <span class="emphasis"><em>itrig</em></span> -- if greater than zero the opcode
    executes the command; otherwise it is an null operation.
    </p>
      </div>
      <div class="refsect1">
        <a id="idp154777104"></a>
        <h2>Performance</h2>
        <p>
      <span class="emphasis"><em>ktrig</em></span> -- if greater than zero and different
    from the value on the previous control cycle the opcode
    executes the command.  Initially this previous value is
    taken as zero.
    </p>
        <p>
      <span class="emphasis"><em>inowait,knowait</em></span> -- if given an non zero the 
      command is run in the background and the command does not wait
      for the result. (default = 0)
    </p>
        <p>
      <span class="emphasis"><em>ires, kres</em></span> -- the return code of the 
      command in wait mode and if the command is run.In other cases 
      returns zero.
    </p>
        <p>
      More than one system command (a script) can be executed with a single <span class="command"><strong>system</strong></span> opcode by using double braces strings {{ }}.
    </p>
        <div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
          <table border="0" summary="Note">
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                <img alt="[Note]" src="images/note.png" />
              </td>
              <th align="left">Note</th>
            </tr>
            <tr>
              <td align="left" valign="top">
      This opcode is very system dependant, so should be used with extreme care (or not used) if platform neutrality is desired.
    </td>
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      <div class="refsect1">
        <a id="idp154782912"></a>
        <h2>Example</h2>
        <p>
      Here is an example of the system_i opcode. It uses the file <a class="ulink" href="examples/system.csd" target="_top"><em class="citetitle">system.csd</em></a>.

      </p>
        <div class="example">
          <a id="idp154784688"></a>
          <p class="title">
            <strong>Example 892. Example of the system opcode.</strong>
          </p>
          <div class="example-contents">
            <p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
            <pre class="programlisting">
<span class="csdtag">&lt;CsoundSynthesizer&gt;</span>
<span class="csdtag">&lt;CsOptions&gt;</span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out   Audio in</span>
-odac          <span class="comment">; -iadc    ;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o system.wav -W ;;; for file output any platform</span>
<span class="csdtag">&lt;/CsOptions&gt;</span>
<span class="csdtag">&lt;CsInstruments&gt;</span>

<span class="comment">; Initialize the global variables.</span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">kr</span> <span class="op">=</span> 4410
<span class="ohdr">ksmps</span> <span class="op">=</span> 10
<span class="ohdr">nchnls</span> <span class="op">=</span> 1

<span class="oblock">instr</span> 1
<span class="comment">; Waits for command to execute before continuing</span>
ires <span class="opc">system_i</span> 1,{{     ps
            <span class="opc">date</span>
            cd <span class="op">~</span><span class="op">/</span>Desktop
            <span class="opc">pwd</span>
            ls <span class="op">-</span>l
            whois csounds.com
        }}
<span class="opc">print</span> ires
<span class="opc">turnoff</span>
<span class="oblock">endin</span>

<span class="oblock">instr</span> 2
<span class="comment">; Runs command in a separate thread</span>
ires <span class="opc">system_i</span> 1,{{     ps
            <span class="opc">date</span>
            cd <span class="op">~</span><span class="op">/</span>Desktop
            <span class="opc">pwd</span>
            ls <span class="op">-</span>l
            whois csounds.com
        }}, 1

<span class="opc">print</span> ires
<span class="opc">turnoff</span>
<span class="oblock">endin</span>

<span class="csdtag">&lt;/CsInstruments&gt;</span>
<span class="csdtag">&lt;CsScore&gt;</span>

<span class="comment">; Play Instrument #1 for thirty seconds.</span>
<span class="stamnt">i</span> 1 0 1
<span class="stamnt">i</span> 2 5 1
<span class="stamnt">e</span>


<span class="csdtag">&lt;/CsScore&gt;</span>
<span class="csdtag">&lt;/CsoundSynthesizer&gt;</span>
</pre>
          </div>
        </div>
        <p><br class="example-break" />
    </p>
      </div>
      <div class="refsect1">
        <a id="idp154789008"></a>
        <h2>Credits</h2>
        <p>
      </p>
        <table border="0" summary="Simple list" class="simplelist">
          <tr>
            <td>Author: John ffitch</td>
          </tr>
          <tr>
            <td>2007</td>
          </tr>
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        <p>
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        <p>New in version 5.06</p>
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